Snap Circuits Sound Electronics Exploration Kit | 185 Fun STEM Projects | 4-Color Project Manual | 40+  Snap Modules | Unlimited Fun Keyboard with optical Theremin Voice changer; Record voice or music and play it back at different speeds Sound energy demonstration and Color changing light Creates Echo effects Connect to your smart phone and analyze sounds with apps Explore both sound and electronics with this innovative kit Projects include, an Optical Theremin, Echo effects, Voice changer - Record voice or music Connect the unit to your smart phone and analyze sounds with downloadable apps Color organ controlled by iPod or other MP3 player, voice or finger Includes full-color manual with easy to follow instructions